Two-way raid controller with programmable host interface for a semiconductor storage device

ABSTRACT

Provided is a two-way RAID controlled storage device of a serial attached small computer system interface/serial advanced technology attachment (PCI-Express) type, which provides data storage/reading services through a PCI-Express interface. The RAID controller typically comprises multiple sets of RAID equipment coupled to one another via a hardware host connect, an adaptive host interface controller, a host connect controller, a two-way RAID controller, a disk connect controller, an adaptive disk mount controller, and a hardware disk connect. Coupled to the hardware disk connect are a set of DDR, SSD memory disk units. Further, each set of RAID equipment typically comprises a programmable host interface unit, a disk controller, a high speed host interface, a disk monitoring unit, a disk plug and play controllers, and a programmable disk mount.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related in some aspects to commonly-owned,co-pending application Ser. No. 12/758,937, entitled SEMICONDUCTORSTORAGE DEVICE”, filed on Apr. 13, 2010. This application is alsorelated in some aspects to commonly-owned, co-pending application Ser.No. 12/763,701 entitled RAID CONTROLLED SEMICONDUCTOR STORAGE DEVICE”,filed on Apr. 20, 2010. This application is related in some aspects tocommonly-owned, co-pending application Ser. No. 12/763,688, entitledRAID CONTROLLER FOR A SEMICONDUCTOR STORAGE DEVICE”, filed on Apr. 20,2010. This application is related in some aspects to commonly-owned,co-pending application Ser. No. 12/848,348, entitled RAID CONTROLLERHAVING MULTI PCI BUS SWITCHING”, filed on Aug. 2, 2010.

FIELD OF THE INVENTION

The present invention relates to a two-way RAID controller for asemiconductor storage device of a serial attached small computer systeminterface/serial advanced technology. Specifically, the presentinvention relates to a storage device of a PCI-Express type forproviding data storage/reading services through a PCI-Express interface.

BACKGROUND OF THE INVENTION

As the need for more computer storage grows, more efficient solutionsare being sought. As is know, there are various hard disk solutions thatstores/reads data in a mechanical manner as a data storage medium.Unfortunately, data processing speed associated with hard disks is oftenslow. Moreover, existing solutions still use interfaces that cannotcatch up with the data processing speed of memory disks havinghigh-speed data input/output performance as an interface between thedata storage medium and the host. Therefore, there is a problem in theexisting are in that the performance of the memory disk cannot beproperty utilized.

SUMMARY OF THE INVENTION

Provided is a two-way RAID controlled storage device of a serialattached small computer system interface/serial advanced technologyattachment (PCI-Express) type, which provides data storage/readingservices through a PCI-Express interface. The RAID controller typicallycomprises multiple sets of RAID equipment coupled to one another via ahardware host connect, an adaptive host interface controller, a hostconnect controller, a two-way RAID controller, a disk connectcontroller, an adaptive disk mount controller, and a hardware diskconnect. Coupled to the hardware disk connect are a set of DDR, SSDmemory disk units. Further, each set of RAID equipment typicallycomprises a programmable host interface unit, a disk controller, a highspeed host interface, a disk monitoring unit, a disk plug and playcontrollers, and a programmable disk mount.

A first aspect of the present invention provides a RAID controller withprogrammable host interface for a semiconductor storage device (SSD),comprising: a first set of RAID equipment comprising a firstprogrammable host interface, first a disk controller, a first high speedhost interface, a first programmable disk mount, a first disk monitoringunit, and a first disk plug and play controller; a second set of RAIDequipment comprising a second programmable host interface, second a diskcontroller, a second high speed host interface, a second programmabledisk mount, a second disk monitoring unit, and a second disk plug andplay controller; and a set of control equipment coupling the first setof RAID equipment to the second set of RAID equipment, the set ofcontrol equipment comprising a hardware host connect, an adaptive hostinterface controller, a host connect controller, a two-way RAIDcontroller, a disk connect controller, and a hardware disk connect; anda set of SSD memory disk units coupled to the hardware disk connect, theset of SSD memory disk units comprising a set of volatile semiconductormemories.

A second aspect of the present invention provides a RAID controller withprogrammable host interface for a semiconductor storage device (SSD),comprising: a plurality of sets of RAID equipment, each of the pluralityof RAID equipment comprising a programmable host interface, a diskcontroller, a high speed host interface, a programmable disk mount, adisk monitoring unit, and a disk plug and play controller; a set ofcontrol equipment coupling the plurality of sets of RAID equipment toone another, the set of control equipment comprising a hardware hostconnect, an adaptive host interface controller, a host connectcontroller, a two-way RAID controller, a disk connect controller, and ahardware disk connect; and a set of SSD memory disk units coupled to thehardware disk connect, the set of SSD memory disk units comprising a setof volatile semiconductor memories.

A third aspect of the present invention provides a method for formingRAID controller with programmable host interface for a semiconductorstorage device (SSD), comprising: providing a first set of RAIDequipment comprising a first programmable host interface, first a diskcontroller, a first high speed host interface, a first programmable diskmount, a first disk monitoring unit, and a first disk plug and playcontroller; providing a second set of RAID equipment comprising a secondprogrammable host interface, second a disk controller, a second highspeed host interface, a second programmable disk mount, a second diskmonitoring unit, and a second disk plug and play controller; andcoupling the first set of RAID equipment to the second set of RAIDequipment using a set of control equipment, the set of control equipmentcomprising a hardware host connect, an adaptive host interfacecontroller, a host connect controller, a two-way RAID controller, a diskconnect controller, and a hardware disk connect; and coupling a set ofSSD memory disk units coupled to the hardware disk connect, the set ofSSD memory disk units comprising a set of volatile semiconductormemories.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a diagram schematically illustrating a configuration of a RAIDcontrolled storage device of a serial attached small computer systeminterface/serial advanced technology attachment (PCI-Express) typeaccording to an embodiment.

FIG. 2 is a more specific diagram of a RAID controller coupled to a setof SSDs.

FIG. 3 is a diagram of the RAID controller of FIGS. 1 and 2.

FIG. 4 is a diagram schematically illustrative a configuration of thehigh speed SSD of FIG. 1.

FIG. 5 is a diagram schematically illustrating a configuration of acontroller unit in FIG. 1.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention, and therefore should not be considered aslimiting the scope of the invention. In the drawings, like numberingrepresents like elements.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments now will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsare shown. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth therein. Rather, these exemplary embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of this disclosure to those skilled in the art.In the description, details of well-known features and techniques may beomitted to avoid unnecessarily obscuring the presented embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of this disclosure.As used herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Furthermore, the use of the terms “a”, “an”, etc., do notdenote a limitation of quantity, but rather denote the presence of atleast one of the referenced items. It will be further understood thatthe terms “comprises” and/or “comprising”, or “includes” and/or“including”, when used in this specification, specify the presence ofstated features, regions, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or groups thereof. Moreover, as used herein, the termRAID means redundant array of independent disks (originally redundantarray of inexpensive disks). In general, RAID technology is a way ofstoring the same data in different places (thus, redundantly) onmultiple hard disks. By placing data on multiple disks, I/O(input/output) operations can overlap in a balanced way, improvingperformance. Since multiple disks increase the mean time betweenfailures (MTBF), storing data redundantly also increases faulttolerance.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art. It will be further understood that termssuch as those defined in commonly used dictionaries should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and the present disclosure, and will notbe interpreted in an idealized or overly formal sense unless expresslyso defined herein.

Hereinafter, a RAID storage device of a serial attached small computersystem interface/serial advanced technology attachment (PCI-Express)type according to an embodiment will be described in detail withreference to the accompanying drawings.

As indicated above, embodiments of the present invention provide a RAIDcontroller for a storage device of a serial attached small computersystem interface/serial advanced technology attachment (PCI-Express)type that supports a low-speed data processing speed for a host. This istypically accomplished by: adjusting a synchronization of a data signaltransmitted/received between the host and a memory disk during datacommunications between the host and the memory disk through aPCI-Express interface; and by simultaneously supports a high-speed dataprocessing speed for the memory disk, thereby supporting the performanceof the memory to enable high-speed processing in an existing interfaceenvironment at the maximum.

Provided is a two-way RAID controlled storage device of a serialattached small computer system interface/serial advanced technologyattachment (PCI-Express) type, which provides data storage/readingservices through a PCI-Express interface. The RAID controller typicallycomprises multiple sets of RAID equipment coupled to one another via ahardware host connect, an adaptive host interface controller, a hostconnect controller, a two-way RAID controller, a disk connectcontroller, an adaptive disk mount controller, and a hardware diskconnect. Coupled to the hardware disk connect are a set of DDR, SSDmemory disk units. Further, each set of RAID equipment typicallycomprises a programmable host interface unit, a disk controller, a highspeed host interface, a disk monitoring unit, a disk plug and playcontrollers, and a programmable disk mount.

The storage device of a serial attached small computer systeminterface/serial advanced technology attachment (PCI-Express) typesupports a low-speed data processing speed for a host by adjustingsynchronization of a data signal transmitted/received between the hostand a memory disk during data communications between the host and thememory disk through a PCI-Express interface, and simultaneously supportsa high-speed data processing speed for the memory disk, therebysupporting the performance of the memory to enable high-speed dataprocessing in an existing interface environment at the maximum. It isunderstood in advance that although PCI-Express technology will beutilized in a typical embodiment, other alternatives are possible. Forexample, the present invention could utilize SAS/SATA technology inwhich a SAS/SATA type storage device is provided that utilizes aSAS/SATA interface

Referring now to FIG. 1, a diagram schematically illustrating aconfiguration of a PCI-Express type, RAID controlled storage device(e.g., for providing storage for a serially attached computer device)according to an embodiment of the invention is shown. As depicted, FIG.1 shows a RAID controlled PCI-Express type storage device according toan embodiment includes a memory disk unit 100 comprising a plurality ofmemory disks having with a plurality of volatile semiconductor memories(also referred to herein as high speed SSDs 100); a RAID controller 800coupled to SSDs 100; a (e.g., PCI-Express host) interface unit 200interfaces between the memory disk unit and a host; a controller unit300; an auxiliary power source unit 400 that is charged to maintain apredetermined power using the power transferred from the host throughthe PCI-Express host interface unit; a power source control unit 500that supplies the power transferred from the host through thePCI-Express host interface unit to the controller unit, the memory diskunit, the backup storage unit, and the backup control unit, and when thepower transferred from the host through the PCI-Express host interfaceunit is blocked or an error occurs in the power transferred from thehost, receives power from the auxiliary power source unit and suppliesthe power to the memory disk unit through the controller unit; a backupstorage unit 600 stores data of the memory disk unit; and a backupcontrol unit 700 that backs up data stored in the memory disk unit inthe backup storage unit, according to an instruction from the host orwhen an error occurs in the power transmitted from the host.

The memory disk unit 100 includes a plurality of memory disks providedwith a plurality of volatile semiconductor memories for high-speed datainput/output (for example, DDR, DDR2, DDR3, SDRAM, and the like), andinputs and outputs data according to the control of the controller 300.The memory disk unit 100 may have a configuration in which the memorydisks are arrayed in parallel.

The PCI-Express host interface unit 200 interfaces between a host andthe memory disk unit 100. The host may be a computer system or the like,which is provided with a PCI-Express interface and a power source supplydevice.

The controller unit 300 adjusts synchronization of data signalstransmitted/received between the PCI-Express host interface unit 200 andthe memory disk unit 100 to control a data transmission/reception speedbetween the PCI-Express host interface unit 200 and the memory disk unit100.

Referring now to FIG. 2, a more detailed diagram of a RAID controlledSSD 810 is shown. As depicted, a PCI-e type RAID controller 800 can bedirectly coupled to any quantity of SSDs 100. Among other things, thisallows for optimum control of SSDs 100. Among other things, the use of aRAID controller 800:

-   -   1. Supports the current backup/restore operations.    -   2. Provides additional and improved back up function by        performing the following:        -   a) The internal backup controller determines the Backup            (user's request Order or the status monitor detects power            supply problems);        -   b) The Internal backup controller requests a data backup to            SSDs;        -   c) The internal backup controller requests internal backup            device to backup data immediately;        -   d) Monitors the status of the backup for the SSDs and            Internal backup controller; and        -   e) Reports the Internal backup controller's status and            end-op.    -   3. Provides additional and improved Restore function by        performing the following:        -   a) The internal backup controller determines the Restore            (user's request Order or the status monitor detects power            supply problems);        -   b) The internal backup controller requests a data restore to            the SSDs;        -   c) The internal backup controller requests internal backup            device to restore data immediately;        -   d) Monitors the status of the restore for the SSDs and            Internal backup controller; and        -   e) Reports the Internal backup controller status and end-op.

Referring now to FIG. 3, a diagram of the RAID controller 800 of FIGS. 1and 2 as coupled to a set (at least one) of SSD memory disk units 100 isshown in greater detail (collectively shown as unit 810 in FIG. 1). Asdepicted, RAID controller generally 800 comprises a first set of RAIDcircuitry 801A and a second set of RAID circuitry 801B that areinterconnected/coupled to one another via host connect controller 880,two-way RAID controller 890, and disk connect controller 895. It isunderstood that although two sets of circuitry 801A-B are shown, theteachings recited herein could accommodate any quantity thereof. Forexample, three sets of circuitry could be provided. Two have been shownin FIG. 3 for illustrative purposes only.

Regardless, sets of RAID circuitry 801A-B include (respectively):programmable host interfaces 820A-B; disk controllers 830A-B coupled tohost interfaces 820A-B A-B; and high- speed host interfaces 840A-B. Alsocoupled to disk controllers 830A-B are disk monitoring units 860A-B,which are coupled to programmable disk mounts 850A-B. As further shown,sets of RAID circuitry 801A-B are coupled to one another via a set ofcontrol circuitry 803 that comprises a hardware host connect unit 992, ahardware host connect controller 880, an adaptive host interfacecontroller, a two-way RAID controller 890, a disk connect controller895, and a hardware disk connect 884, which is coupled to set of SSDmemory disk units 100.

In general, SSD memory disk units 100 are coupled to disk connectcontroller 895, which is coupled to disk mounts 850A -B and are detectedby disk monitoring units 860A-B. Disk plug and play (PnP controllers870A-B) control the functions and/or detection functions related to diskmounts 850A-B. In general, RAID controller 800 controls the operation ofSSD memory disk units 100. This includes the detection of SSD memorydisk units 100, the storage and retrieval of data there from, etc. Ingeneral, two-way RAID controller 890 analyzes the status of diskcontroller 830A-B and determines a appropriate data path. Host connectcontroller 880 controls host interfaces 820A-B. Moreover, as indicatedabove, disk connect controller 895 controls the link between the SSDmemory disk units 100 and disk mounts 850A-B. In general, the embodimentshown in FIG. 3 provides a more stable operation between SSD memory diskunits 100 and the data path, and allows for real-time selection betweenthe two data paths provided by circuitry 801A and 801B, respectively.

Referring now to FIG. 4, a diagram schematically illustrative aconfiguration of the high speed SSD 100 is shown. As depicted,SSD/memory disk unit 100 comprises a (e.g., PCI-Express host) hostinterface 202 (which can be interface 200 of FIG. 1, or a separateinterface as shown), a DMA controller 302 interfacing with a backupcontrol module 700, an ECC controller, and a memory controller 306 forcontrolling one or more blocks 604 of memory 602 that are used as highspeed storage.

Referring now to FIG. 5, the controller unit 300 of FIG. 1 is shown ascomprising: a memory control module 310 which controls data input/outputof the SSD memory disk unit 100; a DMA control module 320 which controlsthe memory control module 310 to store the data in the SSD memory diskunit 100, or reads data from the SSD memory disk unit 100 to provide thedata to the host, according to an instruction from the host receivedthrough the PCI-Express host interface unit 200; a buffer 330 whichbuffers data according to the control of the DMA control module 320; asynchronization control module 340 which, when receiving a data signalcorresponding to the data read from the SSD memory disk unit 100 by thecontrol of the DMA control module 320 through the DMA control module 320and the memory control module 310, adjusts synchronization of a datasignal so as to have a communication speed corresponding to aPCI-Express communications protocol to transmit the synchronized datasignal to the PCI-Express host interface unit 200, and when receiving adata signal from the host through the PCI-Express host interface unit200, adjusts synchronization of the data signal so as to have atransmission speed corresponding to a communications protocol (forexample, PCI, PCI-x, or PCI-e, and the like) used by the SSD memory diskunit 100 to transmit the synchronized data signal to the SSD memory diskunit 100 through the DMA control module 320 and the memory controlmodule 310; and a high-speed interface module 350 which processes thedata transmitted/received between the synchronization control module 340and the DMA control module 320 at high speed. Here, the high-speedinterface module 350 includes a buffer having a double buffer structureand a buffer having a circular queue structure, and processes the datatransmitted/received between the synchronization control module 340 andthe DMA control module 320 without loss at high speed by buffering thedata and adjusting data clocks.

Referring back to FIG. 1, auxiliary power source unit 400 may beconfigured as a rechargeable battery or the like, so that it is normallycharged to maintain a predetermined power using power transferred fromthe host through the PCI-Express host interface unit 200 and suppliesthe charged power to the power source control unit 500 according to thecontrol of the power source control unit 500.

The power source control unit 500 supplies the power transferred fromthe host through the PCI-Express host interface unit 200 to thecontroller unit 300, the SSD memory disk unit 100, the backup storageunit 600A-B, and the backup control unit 700.

In addition, when an error occurs in a power source of the host becausethe power transmitted from the host through the PCI-Express hostinterface unit 200 is blocked, or the power transmitted from the hostdeviates from a threshold value, the power source control unit 500receives power from the auxiliary power source unit 400 and supplies thepower to the SSD memory disk unit 100 through the controller unit 300.

The backup storage unit 600A-B is configured as a low-speed non-volatilestorage device such as a hard disk and stores data of the SSD memorydisk unit 100.

The backup control unit 700 backs up data stored in the SSD memory diskunit 100 in the backup storage unit 600A-B by controlling the datainput/output of the backup storage unit 600A-B and backs up the datastored in the SSD memory disk unit 100 in the backup storage unit 600A-Baccording to an instruction from the host, or when an error occurs inthe power source of the host due to a deviation of the power transmittedfrom the host deviates from the threshold value.

The storage device of a serial-attached small computer systeminterface/serial advanced technology attachment (PCI-Express) typesupports a low-speed data processing speed for a host by adjustingsynchronization of a data signal transmitted/received between the hostand a memory disk during data communications between the host and thememory disk through a PCI-Express interface, and simultaneously supportsa high-speed data processing speed for the memory disk, therebysupporting the performance of the memory to enable high-speed dataprocessing in an existing interface environment at the maximum.

While the exemplary embodiments have been shown and described, it willbe understood by those skilled in the art that various changes in formand details may be made thereto without departing from the spirit andscope of this disclosure as defined by the appended claims. In addition,many modifications can be made to adapt a particular situation ormaterial to the teachings of this disclosure without departing from theessential scope thereof. Therefore, it is intended that this disclosurenot be limited to the particular exemplary embodiments disclosed as thebest mode contemplated for carrying out this disclosure, but that thisdisclosure will include all embodiments falling within the scope of theappended claims.

The foregoing description of various aspects of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed and, obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to aperson skilled in the art are intended to be included within the scopeof the invention as defined by the accompanying claims.

1. A RAID controller with programmable host interface for asemiconductor storage device (SSD), comprising: a first set of RAIDequipment comprising a first programmable host interface, first a diskcontroller, a first high speed host interface, a first programmable diskmount, a first disk monitoring unit, and a first disk plug and playcontroller; a second set of RAID equipment comprising a secondprogrammable host interface, second a disk controller, a second highspeed host interface, a second programmable disk mount, a second diskmonitoring unit, and a second disk plug and play controller; and a setof control equipment coupling the first set of RAID equipment to thesecond set of RAID equipment, the set of control equipment comprising ahardware host connect, an adaptive host interface controller, a hostconnect controller, a two-way RAID controller, a disk connectcontroller, and a hardware disk connect; and a set of SSD memory diskunits coupled to the hardware disk connect, the set of SSD memory diskunits comprising a set of volatile semiconductor memories.
 2. The RAIDcontroller of claim 1, further comprising a controller unit coupled tothe RAID controller.
 3. The RAID controller of claim 2, furthercomprising: a backup storage unit coupled to the controller which storesdata of the set of SSD memory disk units; and a backup control unitcoupled to the controller which backs up data stored in the set of SSDmemory disk units in the backup storage unit according to an instructionfrom the host, or when an error occurs in the power transmitted from ahost.
 4. The RAID controller of claim 2, further comprising a auxiliarypower source and a power control unit coupled it the backup controlunit.
 5. The RAID controller of claim 1, the set of SSD memory diskunits comprising: a host interface unit; a DMA controller coupled to thehost interface unit; an ECC controller coupled to the DMA controller; amemory controller coupled to the ECC controller; and a memory arraycoupled to the memory controller, the memory array comprising at leastone memory block.
 6. The RAID controller of claim 1, the set of SSDmemory disk units providing storage for at least one attached computerdevice.
 7. A RAID controller with programmable host interface for asemiconductor storage device (SSD), comprising: a plurality of sets ofRAID equipment, each of the plurality of RAID equipment comprising aprogrammable host interface, a disk controller, a high speed hostinterface, a programmable disk mount, a disk monitoring unit, and a diskplug and play controller; a set of control equipment coupling theplurality of sets of RAID equipment to one another, the set of controlequipment comprising a hardware host connect, an adaptive host interfacecontroller, a host connect controller, a two-way RAID controller, a diskconnect controller, and a hardware disk connect; and a set of SSD memorydisk units coupled to the hardware disk connect, the set of SSD memorydisk units comprising a set of volatile semiconductor memories.
 8. TheRAID controller of claim 7, further comprising a controller unit coupledto the RAID controller.
 9. The RAID controller of claim 8, furthercomprising: a backup storage unit coupled to the controller which storesdata of the set of SSD memory disk units; and a backup control unitcoupled to the controller which backs up data stored in the set of SSDmemory disk units in the backup storage unit according to an instructionfrom the host, or when an error occurs in the power transmitted from ahost.
 10. The RAID controller of claim 8, further comprising a auxiliarypower source and a power control unit coupled it the backup controlunit.
 11. The RAID controller of claim 7, the set of SSD memory diskunits comprising: a host interface unit; a DMA controller coupled to thehost interface unit; an ECC controller coupled to the DMA controller; amemory controller coupled to the ECC controller; and a memory arraycoupled to the memory controller, the memory array comprising at leastone memory block.
 12. The RAID controller of claim 7, the set of SSDmemory disk units providing storage for at least one attached computerdevice.
 13. A method for forming RAID controller with programmable hostinterface for a semiconductor storage device (SSD), comprising:providing a first set of RAID equipment comprising a first programmablehost interface, first a disk controller, a first high speed hostinterface, a first programmable disk mount, a first disk monitoringunit, and a first disk plug and play controller; providing a second setof RAID equipment comprising a second programmable host interface,second a disk controller, a second high speed host interface, a secondprogrammable disk mount, a second disk monitoring unit, and a seconddisk plug and play controller; and coupling the first set of RAIDequipment to the second set of RAID equipment using a set of controlequipment, the set of control equipment comprising a hardware hostconnect, an adaptive host interface controller, a host connectcontroller, a two-way RAID controller, a disk connect controller, and ahardware disk connect; and coupling a set of SSD memory disk unitscoupled to the hardware disk connect, the set of SSD memory disk unitscomprising a set of volatile semiconductor memories.
 14. The method ofclaim 13, further comprising coupling a controller unit to the RAIDcontroller.
 15. The method of claim 14, further comprising: coupling abackup storage unit to the controller which stores data of the set ofSSD memory disk units; and coupling a backup control unit to thecontroller which backs up data stored in the set of SSD memory diskunits in the backup storage unit according to an instruction from thehost, or when an error occurs in the power transmitted from a host. 16.The method of claim 14, further comprising coupling an auxiliary powersource and a power control unit to the backup control unit.
 17. Themethod of claim 13, the set of SSD memory disk units comprising: a hostinterface unit; a DMA controller coupled to the host interface unit; anECC controller coupled to the DMA controller; a memory controllercoupled to the ECC controller; and a memory array coupled to the memorycontroller, the memory array comprising at least one memory block. 18.The method of claim 13, the set of SSD memory disk units providingstorage for at least one attached computer device.